This is almost always solved by deleting the sm directory contents.

Well, not if you have images with different versions of SM in the same directory. I encountered this problem recently where I switched between my "BFAV-image" (which is not always up to the latest) and my "experimental one" (which is up-to-date) a couple of times. There is apparently some really weird problem (not sure where it's coming from) if SqueakMap has initialized once already - deleting the sm directory leads to spurious errors then.

This made me wonder if SM shouldn't use sub-directories of the SM directory indexed by UUID or somesuch to differentiate between the "incarnations" of SM itself. Seems to me that this may be the easiest way to solve that trouble (hopefully) once and for all.

Cheers, - Andreas